Electbolytic condenser



Patented July 31, 1923.

UNITED STATES PATENT OFFICE.

LEWIS W. CHUIBB, OF P I'ITSBURGH, PENNSYLVANIA, ASSIGIIOR TOWESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATIONOFPENNSYLVANIA ELECTROLYTIC CONDENSER.

Application filed December 30, 1919. Serial No. 348,444.

To all whom it may concern-7 Bef'it known that I, LEWIS W. CHUBB, acitizen of the United States, and a resident of Pittsburgh, in thecounty of 'Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Electrolytic Condensers, of which the following isa s ecification.

y invention relates to electrolytic condenscrs and it has, for itsprimary object, the construction of condensers which shall providesatisfactory power-factor correction under continuous operatingconditions.

It is well known to those familiar with the art that condensers, of thetype formed by employing a plurality'of fi plates immersed in a suitableelectrolyte, connected in 'a powensupply circuit; for power-factorcorrection, or for other purposes, tend to become unstable and operatewith an increased power factor or with increased losses. This unstableconditionobtains when the volta e impressed upon one of the electrodesis slightly higher than on the other, which causes the-electrode havingthe higher impressed volt e'tovhave less capacitance than the othehis'unbalanced condition-becomes aggravated and, if it i's not relievedin some mannergthe condenser electrode having the lower capacitanceincreases to the break-down voltage and produces high losses occasionedby the anode leakage, or sparkling.

One object-of my invention, thereiore,re-

- sides in the provision of apparatus that shall insure satisfactoryoperating conditions in a condenser which is continuously connected in apower circuit.

, Another object of my invention is to provide apparatus, which may beemployed in conjunction with an electrolytic condenser to insure goodoperating characteristics, which shall be relatively inexpensive, simplein construction and easil repaired With these and other objects in view,my invention will be more fully described, illustrated in the drawin inthe several iews of which correspon ing numerals indicate like parts,and then particularly pointed out in the claims.

In the drawings, Fig. 1 is a diagrammatic view of an electrolyticcondenser having a -forming convenientto have. them readilyinspe'cte'dto insure satisfactory operation. In practicing my invention, therefore,I provide apparatus for insuring-stableoperation of an electrolyticcondenser which may be connec ted' in a power circuit andjnot subject toinspection exceptat convenient, and perhaps mfrequent intervals. I maemploy a dynamometer type of relay whi is operated by'a diiference inpotential betweenthe main gelectrodes, The relay automatically connectsan auxiliary electrode of relatively low; capacitance; on'e ofjthemainelectrodes fwh chffis ofhigher' potential than the other toi'threbyincrease, the capacitance-of the electrodehaving the highr'potential'and thereby" cause its potential to be reduced to that of the otherelectrode.

To insure a clear understanding of my invention, I have shown, in Fig.1,. an electrolytic condenser, 1 oompris' a tank 2 containinanelec'trolyte 3,in viich aplurality of mam electrode's'd and 5'areimmersed. The main electrodes 4 and 5 are co f l ected to a secondarywinding 6 of a' transformer or to a balancing impedance device. I preferto'e'mp'loy a. dynamo meter ty of relay]? which comprises a core mem er8 having a winding 9 surrounding a portion of the core and connected inserieswith a' non-inductive resistor 9 and across the supply circuit, orin parallel relation to the secondary winding 6, as indicated at 10 and11. A rotatable armature member 12 is mounted upon ashaft 13, upon whichacontact arm 14 is ri idly mounted and is adapted to engage either of aplurality of contact members 15 and 16 which.are connected to theelectrodes 4 and 5', respectively. The

frequently located in places where it, is inarmature 12 on its shaft 13is disposed be 1 tween the ends of the core member 8. A current coil 17is wound about the armature 12 and is connected, at one end, through acondenser 18 and a resistoii-l f to"the midoint'bf the secondary winding6 and, at its other end, to a small electrode which is immersed-in theelectrolyte 3. An auxiliaigy film-forming electrode 21, which ispreferably of less area than the main electrodes 4 and 5, isconnectedto' the arm 14 direction of the current. through the coilw1'7,ffivhenthearmature 12 is rotated, the arm"1'4iengages one ofthecontact members 15"a'nd '16 and. connects the auxiliary electrode '21to the main electrode having the higher'potehtial: The condenser 18 isconr'lcteii in serieswith the current coil 17 to iejvenc "any fiowjofdirect current through t ecbil' 17;"but it, permits of free passage ofalternating current when unbalanced volurge conditions obtain. On"account of the fact that thecondenser 18 tends to establishaqiiadrature'current'in the coil 17 and, since themil 9" is' essentiallya reactance device 'whichnl'so takes lquadrature current, it isdesirable to connect theresistor 19 in series the condenser- 18 to bringthe current in the 'eoi l I7 s'ub stantially in phase with the potentialdifference between the electrol be?) and the mid-point of the winding 61he resistor 9" in the field circuit keeps the current and field flux inthe core 8 substliflitially in time" phase with thefp'otential adroslsthe' electrodes 4 and 5! This insures the'fc'omponentfields of the relaydevice 7 being in time phase and giving the required tor ue.f

enithe total voltage across winding 6 is equally divided between theelectrodes 4 and 5, the potential of electrode 20 is the same ast-hat ofthe midpoint of winding 6 and, therefore, there is'no flow of currentthrough coil 17. When the voltage on one of the electrodes 4 or 5increases, there arises a difi'erence of potential between the electrode20 and the midpoint of winding 6, the magnitude and direction of whichcauses a current to flow in the corresponding direction between the'saidpoints, thus energizing' the coil 17 'and movino' contactor 14'to addelectrode area 21 to either of the main electrodes 1 and 5. After a timethe voltage between electrodes 4 and 5 becomes equalized and the coil 17is decncrgized, causing the contactor 14 to more into its neutralposition and disconnectingelectrode "21 from the circuit. When thevoltage again becomes unbalanced, the cycle is repeated.

It will be appreciated from the foregoing description that any unstablevoltage conditions will cause the relay 7 to actuate the lever arm '14and connect the auxiliary electrode 21 to the main electrode which ishaving the higher alternating potential impressed thereon. Thefluttering relay device will thus keep the voltage balanced by changingthe connections of the auxiliary e ectrode from side to, side. The formof relay shown in this instance provides for connection of the totalcapacity of the auxiliary electrode to the one orthe other of the mainelectrodes when the voltage is sufiicient- 1y unbalanced. I may providea progressive compensation for-slight variations in voltage conditionsemployed a modified form of my in'vention asshownin Fig. 2. As hereshown, the a m 1'4i adapted to engage any one of aserie s of taps 22which are connected to various points on the winding 6. An additionalcondenser 23 is connected between the auxiliary electrode 2-1 and thearm .14 to reyent the fiow of direct current to the sum iary electrode.

By using a construction, s'uchas shown in Fig. 2, the capacitance of theauxiliary electrode21 is not immediately connected to one electrode or;to the other, as the voltage is varied but is "connected to one of thetaps 22 on the sidecf the windin connected to the electrode having thehigher voltage. The auxiliary electrode 21 is thus connected to the oneor the other of themain electrodes, in a series of steps, by the arm 14making successive engagement with the various ta s22. Such aconstruction may be prefera le, insome instances hccause' a moredelicate adjustment of voltage balance is maintained. 7

It will be apparent,'form the description of the condensers embodying myinvention, that they maybe connected in a power circuit and insuresatisfactory operation without constant attention because the .voltageconditions are maintained in balance and, consequently, the capacitancesof the condenser electrodes are maintained at substantially an equalvalue. Furthermore, the condensers will be longer-lived on account ofthe fact that stable conditions'are maintained. Any corrosive effects onthe plates, occasioned by exceptionally high voltages, will be avoided.

'Although I have shown and specifically described a plurality ofcondensers which embody my invention, it is obvious that slight changesmay be made in their construction and in the electrical connections andconstruction of the relay employed to insure stable operatingconditions, and I desire, therefore, that no limitations shall beimposed except such as are indicated in the appended claims.

I claim as my invention l. The combination with an electrolyticcondenser comprising a plurality of electrodes immersed in anelectrolyte, of means for maintaining the capacitances of the condenserelectrodes substantially equal, said means including a switch which isactuated when the voltage is unequally divided between the electrodes.

2. The combination with an electrolytic condenser comprising a pluralityof main electrodes immersed in an electrolyte, of means for maintainingthe capacitances of the condenser electrodes substantially equal, saidmeans including an auxiliary electrode and means for connecting theauxiliary electrode to a main electrode when the impressed voltage isunequally divided between the main electrodes.

3. The combination with an electrolytic condenser comprising a pluralityof main electrodes immersed in an electrolyte, of means for maintainingthe capacitances of the condenser electrodes substantially equal, saidmeans including an auxiliary electrode of less area than the mainelectrodes, and means for connecting the auxiliary electrode to a mainelectrode when the impressed voltage is unequally divided between themain electrodes.

4. The combination with an electrolytic condenser comprising a pluralityof main electrodes and an auxiliary electrode, all immersed in anelectrolyte, of means for maintaining the capacitances of the condenserelectrodes substantially equal, said means including a lurality ofcontact members connected to t e main electrodes of the condenser, acontact arm connected to the auxiliary electrodes and adapted to engageeither of the contact members, and means for actuating the contact arm,said means being governed by the difi'erence of potential impressed uponthe electrodes of the condenser.

5. The combination with an electrolytic condenser comprising a pluralityof filmforming electrodes and an auxiliary filmfonning electrode of lessarea than the other electrodes, all immersed in an electrolyte, of meansfor maintaining the capacitances of the condenser electrodessubstantially equal, said means including a plurality, of contactmembers connected to the electrodes, a contact arm adapted to engage thecontact members and connected to the auxiliary electrode, a movablesupporting member for the contact arm, and means for moving thesupporting member to cause the contact arm to engage one of the contactmembers when nected to the main electrodes,

mam electrodes and nected to the contact members,

the voltage impressed upon the main electrodes is unequally dividedtherebetween.

6. The combination with an electrolytic condenser comprising a pluralityof main electrodes and an auxiliary electrode of less area than theother electrodes, of means for maintaining the capacitance of the condenser electrodes substantially equal, said means including an impedancedevice connected to the main electrodes, a plurality of contact membersconnected to the impedance device, a contact arm adapted to successivelyengage the contact members and connected to the auxiliary electrode, andmeans for moving the contact arm to engage the contact members governedby the difference in alternating potential between the midpoint of theimpedance device and the electrolyte.

7. The combination with an electrolytic condenser comprising a pluralityof main electrodes and an auxiliary electrode of less area than theother electrodes, of means for maintaining the capacitances of thecondenser electrodes substantially equal, said means including animpedance device cona plurality of contact members connected to theimpedance device at substantially equally spaced intervals, a contactarm adapted t successively engage the contact members and connected totheauxiliary electrode, a condenser connected in serie with the contactarm and the auxiliary electrode, and means for mov ing the contact armto successively engage the contact members controlled by the difference1n alternating potential between the midpoint ofthe impedance device andthe electrolyte.

8. In an electrical power system, an electrolytic condenser comprising aplurality of an auxiliary electrode of less area than the mainelectrodes all immersed in an electrolyte and having the main electrodesconnected to an inductive windmg, a plurality of contact members conwinding, a contact arm connected to the auxiliary electrode and adaptedto make engagement with either of the a rotatable support for thecontact arm, an electrical coil disposed about the rotatable support,means for establishing; a magnetic field about the sup port, an meansfor causing an alternating current to traverse the coil surrounding thesupport when the voltage impressed upon the main electrodes is unequallydivided therebetween, whereby the contact arm is caused to engage one ofthe contact members to connect the auxiliary electrode to the mainelectrode havin the higher potential with respect to the e ectrolyte.

In testimony whereof, I have hereunto subscribed my name this 23rd dayof December, 1919.

LEWIS W. CHUBB.

